With the benefit of hindsight, it all seems quite obvious. MP3 players, like Apple's iPod, in many pockets, audio production software cheap or free, and weblogging an established part of the internet; all the ingredients are there for a new boom in amateur radio.

But what to call it? Audioblogging? Podcasting? GuerillaMedia?

"It's an experiment, really," says Christopher Lydon, the ex-New York Times and National Public Radio journalist, and now a pioneer in the field. "Everything is inexpensive. The tools are available. Everyone has been saying anyone can be a publisher, anyone can be a broadcaster," he says, "Let's see if that works."

Lydon's programmes, downloadable from his weblog, are interviews with webloggers, internet pioneers, and more recently, politicians, as the American presidential election campaigns gain speed.

When I spoke to him, Lydon was in Iowa, reporting for his website from the caucus. With no publisher to appease, no editor to report to, and an abundance of cheap tools, he says he feels unleashed to work directly with his audience.

This, he says, is "something that newspapers can only dream about... they all have an institutional envy (of this)".

By combining the intimacy of voice, the interactivity of a weblog, and the convenience and portability of an MP3 download, Lydon's work seems to take the best of all worlds, and not just for the listener. The ability to broadcast out, and have the internet talk back to them, Lydon says, is very appealing to journalists: professional hack and weblogger alike.

"It's an approach to a different kind of radio. My feeling is that traditional media in America is stuck. Let's think of a new kind of media," he says.

He's not alone in this view. Many people are seeing the "internet as a medium that can garner a great deal of feedback," says Jonathan Korzen, director of public relations for Audible.com. Audible is an American company which started off selling downloadable audio books, but now, Korzen says, its fastest growing market isn't books, but downloadable radio programmes.

They sell subscriptions to recordings of many popular daily American national talk radio shows, and even to read-aloud versions of the New York Times and Wall Street Journal. The freedom given to the listener, of being able to choose when and where to listen to their favourite programming is proving extremely popular.

Add that to the feedback fostered by the increasingly online-savvy listenership that are searching these things out, and you have a potent mix.

Liberating the listeners from time and place, and allowing them to talk back to the programme-makers is one thing: liberating the programme-makers is even better. You can get away with a lot more on the internet.

Case in point: Audible also creates its own programming. Susie Bright, the American sex writer, has a downloadable weekly show, In Bed with Susie Bright, currently on its 145th episode and very popular, despite never having been traditionally broadcast or promoted. "Her show is, in essence, unbroad castable," understates Korzen, "because of her frank language."

Happily, being distributed via the internet, downloadable radio is not subject to any programming regulations. Nor is there a shortage of airtime, previously a major constraint on aspiring radio journalists.

"The business involved in getting something on the radio (in the US) is an onerous one," says Korzen, "but the internet is not fettered by regulations."

Although they currently have no concrete plans, Audible is considering launching a form of "vanity press", perhaps later on this year. This might allow all-comers to sell downloadable radio shows, as well as the major broadcasters. One might soon be able to make a living doing this.

As for the professionals in the UK, none, as yet, offer radio programmes for download. The BBC, for example, allows listeners to stream certain old programmes, depending on the rights owned by the BBC. Radio Four leads in this: its Listen Again page offers much of the previous week's listening.

That these programmes are only available as RealPlayer streams is irrelevant to the determined. Cheap applications are available to record RealPlayer streams, and Windows Media for that matter, and convert them to MP3, ready for a waiting iPod.

The latest versions can even be set to start and stop recording at a certain time, allowing you to time-shift your radio listening, create schedules of your own devising, and then carry it away from your desk.

Curiously, despite the relative ease of ripping radio shows and audio books, there appears to be very little illegal sharing of these files going on. According to Audible's research, Korzen says, this is because the demographic audience who want to listen to talk radio and speaking books, are unlikely to steal them. Stealing music is one thing, he says, but stealing books is just not cool.

While these downloads are all in the traditional radio style, the low cost of producing audio for the internet means more interesting stuff can be done. QuietAmerican.org, for example, is a beautiful collection of sound recordings made while travelling around south-east Asia. Too short and context-free for broadcast, they're perfect for downloading or listening to online. More traditional bloggers, too, are creating little snippets of audio, often by calling a special phone number.

Paid-up users of LiveJournal can do this, as can subscribers to Audblog.com, who can create audio postings to any Movable Type, Radio Userland, LiveJournal or Blogger weblog. LiveJournal's recordings are in Ogg Vorbis format, which few handheld devices can deal with, but Audblogs are in plain old MP3: perfect for pulling down and listening to on the bus.

The battle over which recording format to use is continuous and part of the charm of the cutting edge of internet content. There's MP3 of course, others might like Ogg, more still Wav; One great site, Greasyskillet.org, uses QuickTime audio files. But this all goes to point out the increasingly loud and clear message from these audio producing sites: that this sort of thing is no longer the preserve of the professional, or the rich.

Grant Henninger, a popular weblogger from California, makes a good example. He started to record his own five-minute radio show for his site: "I had planned to make a show, instead of just random thoughts - to show that it could be done," he says. "Other people were already doing it, and they were doing it well - they had shows that sounded like they could go on the radio."

The quality, he said, blew him away, until he did it himself: a cheap microphone, free recording software, a little practice, and Grant - now on his second show, downloadable from his site - sounds just as good. It was, he says, easy.

This discovery, like Lydon's revelation of finding an audience that talks back to him, and like Audible discovering a market for radio programmes that you can carry around and listen to whenever you like, is the final part of the birth of audioblogging. We're going from the ease of putting words online, to the new ease of putting radio there too.

"We will not go back to genuflecting to all these one-way top-down ways of disseminating news," says Lydon. We'll make it ourselves, and listen to it whenever we like.

Talk can be cheap

Technologists have also embraced the idea of downloadable radio programming.

· The Web Talk Guys - Rob and Dana Greenlee - broadcast their show on a handful of local FM stations in the US, but allow anyone to download their shows from their site.

· Craig Crossman's Computer America is freely available, along with many other shows, from BusinessTalkRadio.net.

Not content with timeshifting your radio listening by a few days? How about a few decades? Rusc.com is a members-only site, offering 6,000 American radio shows from the 30s, 40s and 50s. Closer to home, Imperial College Radio archives everything in MP3: downloadable as you wish.